Render handlebars template programmatically

Is it possible to render a Handlebars/Htmlbars-template programmatically inside the controller?

I'm rendering blog-posts and would like to have the ability to replace parts of their content with another HTMLBars-template?

e.g.

My blog post looks like this:

<h3>Lorem ipsum</h3>
<p>dolor sit amet</p>
[mycooltemplate]
<p>another line</p>

In the controller I'd look for [mycooltemplate] and have the same output as if I would invoke {{ render "mycooltemplate" }} or {{ partial "mycooltemplate" }}